The Impact of Aging on an FPGA-Based Physical Unclonable Function

On-chip Physical Unclonable Functions (PUFs) are emerging as a powerful security primitive that can potentially solve several security problems. A PUF needs to be robust against reversible as well as irreversible temporal changes in circuits. While the effect of the reversible temporal changes on PUFs is well studied, it is equally important to analyze the effect of the irreversible temporal changes i.e. aging on PUFs. In this work, we perform an accelerated aging testing on an FPGA-based ring oscillator PUF (RO-PUF) and analyze how it affects the functionality of the PUF. Based on our experiment using a group of 90-nm Xilinx FPGAs, we observe that aging makes PUF responses unreliable. On the other hand, the randomness of PUF responses remains unaffected despite aging.